It looks like you got the player physics to match pretty closely with the original. I'm working on an Alex Kidd port of my own (to a completely different system) and would be interested to know about that part of your implementation, as well as any collision detection related code. Can you tell us a little bit about how you implemented that?

Also, I saw your v2 videos on youtube. That parallax scrolling and those larger levels look awesome. This could be the sequel Alex always deserved but never got .